The Trump administration wants you to believe it's devoted to protecting American taxpayers from supposedly welfare-mooching foreigners. Don't. What President Trump is really doing is shutting the door on all but a small sliver of well-heeled immigrants — while telling the "tired," "poor," and "huddled masses" yearning to put cheap food on American dinner plates to get lost.

There was a time when immigration restrictionists used to insist that they weren't motivated by nativist considerations because their beef was not with legal immigrants, but illegal ones who don't play by the rules. Trump has ripped the mask off that lie. He has slammed literally every law-abiding legal immigrant group — refugees, asylum seekers, foreign family members of Americans, low-skilled immigrants, high-skilled foreign workers on H-1Bs, their wives, foreign students, and even naturalized citizens.

Still, none of that compares with what the administration is planning next.

The Department of Homeland Security is finalizing rules that would make it vastly easier to brand immigrants deemed "likely" to qualify for even minimal social services a "public charge" and make it harder for them to enter the country if they are abroad — or, if they are here, obtain green cards or citizenship or otherwise upgrade their immigration status. It might not even matter if these legal immigrants personally consume these services. It would reportedly be enough that their American children or spouses do. By some estimates, 20 million immigrants may be affected.

The proposed guidance, evidently the brainchild of Stephen Miller, an implacable immigration opponent, is relying on an 1891 law that barred immigrants "likely to become public charges." But this meant — in the evocative language of its time — "idiots, lunatics, convicts," or otherwise indigent or disabled folks who couldn't earn a living and would therefore become a ward of the state. Consistent with this understanding, DHS's 1999 guidance defined "public charge" as anyone who would become "primarily dependent" on cash benefits.

Miller's scheme would brand anyone who receives — or is likely to receive — services or subsidies (barring a few explicitly exempted) worth greater than 3 percent of the poverty line a public charge. This works out to $1 per day for a single person or 50 cents for a family of four, Cato Institute's David Bier points out. Even subsidies to purchase coverage mandated by ObamaCare would count against them. Worse, immigrants don't actually have to avail of these benefits to have their petitions rejected. They or their family simply have to be eligible for these subsidies because they are sick, old, have young children, or don't have unsubsidized coverage — unless they make 250 percent of the poverty level, in which case they'd be exempted.

The administration's intention here is clear: Cut legal, family-based, and low-skilled immigration and allow only the tippy top in.

The perversity of this cannot be overstated.

An immigrant would be barred from upgrading his status if he married, say, an American woman on Social Security disability till he crossed the 250 percent earning threshold. Or consider, a real-life example of a Haitian green-card holder who works 80 hours a week as a nursing assistant but has a severely disabled American daughter who receives public assistance. His citizenship petition may not have a prayer. In effect, Miller's plan would penalize immigrants not because they are needy but because they have Americans in their lives who are.

What's particularly unfair about this is that it's not like legal immigrants get any reprieve from taxes. With very, very few exceptions, they pay all the taxes that Americans do and then some (if you count all the fees that they and their employers have to constantly cough up to get and keep their visas). Denying them a shot at citizenship would mean creating a permanently disenfranchised class that can be taxed but will be barred from basic assistance (in addition to all the federal means-tested benefits), and won't be allowed to vote, eviscerating America's bedrock commitment to no taxation without representation.

There might be a rationale for doing something this draconian if there were any reason to believe that immigrants consume more welfare than the native born. But in fact, the opposite is true.

A recent study by the National Academy of Sciences estimated that an average immigrant arriving today would contribute $150,000 more in taxes than he or she would consume in benefits over their lifetime. But even poorer immigrants tend to consume welfare at lower rates and lower amounts than the native born. Furthermore, even when immigrants receive welfare, they don't quit working: 14 percent more keep their jobs as compared to the native born. And none of this takes into account the fact that immigrants constitute a windfall for America's public coffers given that they tend to come during their peak productive years after another society has borne the cost of raising and educating them. If anything, every working immigrant is a gift to American taxpayers. And when one takes into account the taxes pocketed thanks to the economic growth generated by immigrants, their fiscal impact becomes overwhelmingly positive.

The scheme's biggest tragedy is that it would seriously undermine America's genius in assimilating newcomers. The relative ease with which immigrants have been able to transition from being outsiders to full citizens with full rights has prevented the kind of alienation, ghettoization, and marginalization that has turned many European countries into tinder boxes. America's bargain — no, promise — has been that anyone who works hard, plays by the rules, and craves freedom from stultifying hierarchies of class, caste, and creed can be an American. Allowing the administration to use a fake argument to deny people breaking their backs in farms, meat-packing plants, and construction to make Make America Great everyday would serve neither this country — nor immigrants — well.